1. Field of the Invention
The present invention relates to a solar heat-collecting structure.
2. Description of the Prior Art
Various solar heat-collecting structures have been proposed for heating liquids and then either storing the heated liquids for future use of for circulating the heated liquid to utilize its heating effect.
For example, a solar heat-collecting structure having a flat transparent slanted roof for transmitting solar radiation to a pool of water within an enclosure beneath the roof is disclosed in Rowekamp U.S. Pat. No. 3,161,193. However, the roof configuration is such that it receives direct solar radiation only during a short part of the daylight hours. Furthermore, there is nothing to prevent the loss of reflected heat and solar radiation from the enclosure through the transparent roof structure.
A solar heat collector having a transparent domeshaped roof through which solar radiation is transmitted to a heat collector within an enclosure is shown, for example, in Barry U.S. Pat. No. 2,213,894 and Agnew U.S. Pat. No. 2,636,129. However, such structures have no means for preventing the loss of heat and solar radiation by re-reflection from within the enclosure back through the roof to atmosphere. Also, such structures have no means for unsuring that solar radiation will be directed to the heat-collecting means within the enclosure.
In a solar heat-collecting device as shown in Bowen U.S. Pat. No. 2,872,915, two inwardly facing parabolic mirrors form an enclosure within a heat-collecting pipe is positioned. One of the two parabolic mirrors forms a roof for the enclosure which transmits solar radiation into the enclosure toward the opposite parabolic mirror which forms a floor of the enclosure. The floor mirror reflects the solar radiation toward the heat-collecting pipe. The inner surface of the parabolic roof is coated with a radiation-reflective material to give the inner surface of the roof the properties of a parabolic mirror to minimize heat loss from the structure.
Various solar heat-collecting structures have utilized lenses either alone or in combination with reflectors to concentrate solar radiation on a heat-collecting means within an enclosure to which solar radiation is transmitted. In one such device, shown in the Shipman U.S. Pat. No. 1,638,266, the lenses form a flat roof for transmitting solar radiation into an enclosure. These in turn reflect the solar radiation to a heat-collecting pipe centered within the enclosure. In Freeman U.S. Pat. No. 2,277,311, two layers of staggered hemispherical lenses form a flat roof for a heat-collecting enclosure. Solar radiation is converged by the outer spherical lenses as it is transmitted through the outer layer of lenses and then scattered by the inner layer of lenses within the enclosure toward heat-collecting pipes forming a floor beneath the lenses. In a structure such as shown in Huntoon U.S. Pat. No. 895,761 solar radiation is transmitted through a flat slanted roof to reflectors within an enclosure which reflects the radiation to a single central lens which in turn concentrates the solar radiation on a heat-collecting conduit within the enclosure. In a solar heat-collecting device shown in Nonaka U.S. Pat. No. 3,587,559, two spherical lenses beneath a flat transparent roof converge solar radiation to create an intense heat within the enclosure which is transmitted to heat-collecting pipes interspersed amongst the spherical lenses.
Although the foregoing prior art structures have certain advantageous features, no single such structure combines the advantageous features and discards the disadvantageous features of the other structures in a manner to provide a practical, inexpensive heat collector of optimum efficiency and versatility.